《 简单现象，复杂问题。》 https://tieba.baidu.com/p/8486408857
回复 4 楼，
⊿ L = ʃ ( L0 - dx ) / L0 * m0 * g / ( L0 * k ) dx
= ʃ ( L0 - dx ) m0 g / ( L0 ² k ) dx
= m0 g / ( L0 ² k ) * ʃ ( L0 - dx ) dx
= m0 g / ( L0 ² k ) * [ ʃ L0 dx - ʃ ( dx ) ² ]
= m0 g / ( L0 ² k ) * [ L0 x - ʃ ( dx ) ² ]
标签：L0,复杂,m0,dx,简单,回复 From： https://www.cnblogs.com/KSongKing/p/17520991.html